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View Full Version : Balance Charger for lipo used to charge AAA's?


dr_hfuhuhurr
2011.06.22, 12:29 PM
So the purpose of a balance charger for lipo's is to charge each lipo cell individually. This is basically what I've seen people do with the Hitec X4, charge each AAA cell individually.

Since your average lipo balance charger is setup to already do this, with some fancy wiring to a balance tap you should be able to charge AAA cell individually.

Anyone tried this yet? Or am I completely nuts?

color01
2011.06.22, 01:08 PM
I think technically yeah, you can do this, but a Lipo pack balancer also requires the balancing circuitry to have access to each individual cell in the pack. Unless you hook up an AAA pack to have both charging leads and balancing leads, you can't actually do any of this balancing magic. By the time you do, you might as well have bought a Maha or Lacrosse charger that will just do all four AAA's separately, lol.

dr_hfuhuhurr
2011.06.22, 01:26 PM
True, but the MAHA charger doesn't really do that well for peaking packs.

I've seen people modify the PN charging tray to use the Hitec 4x charger to charge each cell individually. This is pretty much the alternative I'm looking at if I can't get the balance charger thing to work out.

My charging practice would probably be, charge the cells on the MAHA charger, then just before my run, re-peak the cells on the "good" charger.

z3zinho
2011.06.22, 04:27 PM
My guess is you can't. Lipo charges use CC-CV to charge batt's instead of only CC and delta peak. So basicaly, the charger is programmed in a different way, and tries to keep the cell's balanced at a higher voltage.

The idea is good, but modifying a li-po charger is just insane. That is unless you have a lot of electronics knowledge and nothing better to do :D

I would sugest you just get a Lacross/MAHA. Also, look into the Spintec ICC charger. Although designed with sub-c packs in mind, It's a high end charger that does exactly want you're proposing ;)

mikedw
2011.06.22, 05:32 PM
I think that charger is basically 4 nimh chargers in one and each charger charges one cell on the tray. I can't believe you use a balancing tap on a nimh.

themelis factor
2011.06.22, 05:47 PM
So the purpose of a balance charger for lipo's is to charge each lipo cell individually. This is basically what I've seen people do with the Hitec X4, charge each AAA cell individually.

Since your average lipo balance charger is setup to already do this, with some fancy wiring to a balance tap you should be able to charge AAA cell individually.

Anyone tried this yet? Or am I completely nuts?

I use that charger to charge cells individual there isn't a balance charger for nimh come by the track friday and we will talk about it more in depth

bermbuster
2011.06.22, 08:29 PM
Balance charging is not the ideal way to charge a NIMH.
You want to use a peak detection charge.....
Here is the problem with a peak detection charge in a group setting (coventional charging tray) the group of 4 will only be charged to the peak capacity of the weakest individual cell....
Now if your using matched packs there is no problem until age and use creep on the cells.... By using an individual charger like the maha or lacrosse or a multi charger (hitec,etc..) you can group your individual cells into matched packs by sorting similar numbers.
The multi charger shines because you can adjust settings to suit a racing type of scenerio. (more amperage charging and discharging)
I did not take a conventional charging tray and modify it instead I made up 4 charging trays.....using a single aaa battery holder from Newark Electronics.

blt456
2011.06.22, 09:09 PM
True, but the MAHA charger doesn't really do that well for peaking packs.

Most locals at our track use Maha chargers (more than one!) such as the 8-cell and the c9000. Everyone I know who uses these charge and peak, I rarely see any fancy chargers. I personally don't see the need to buy an expensive charger and wire 4 individual trays to it or modify a PN/ATM tray. My maha charges my batteries just fine...

Why not just get the c9000? You can charge each battery at different settings and you get to see its current charge level and voltage. No one at our track has any issues with maha chargers and I would love to see your proof as to why "the MAHA charger doesn't really do that well for peaking packs."

bermbuster
2011.06.22, 09:27 PM
Most locals at our track use Maha chargers (more than one!) such as the 8-cell and the c9000. Everyone I know who uses these charge and peak, I rarely see any fancy chargers. I personally don't see the need to buy an expensive charger and wire 4 individual trays to it or modify a PN/ATM tray. My maha charges my batteries just fine...

Why not just get the c9000? You can charge each battery at different settings and you get to see its current charge level and voltage. No one at our track has any issues with maha chargers and I would love to see your proof as to why "the MAHA charger doesn't really do that well for peaking packs."

I have the 9000 as well and it works great. I use it often. When I came to race with you guys I used a maha c401. The need for the multi charger shows value when you race in a stock motor class. The reality is the multi charger isnt really expensive(mine was $80) it just takes up way too much pit space..... When the racing gets so close it is amazing what racers will do to extract more speed.....:cool:

blt456
2011.06.23, 12:30 AM
I have seen some high end chargers that can charge cells individually that cost a lot...the space is an issue but I still think one is still competitive if they just do regular battery maintenance and don't charge at extremely high rates.. peak 900's and trp "750s" charged at 1 amp and peaked at 2 amps is still good for 80t stock :p

When you first came to ILR, I ran my "normal" 80t in mod class running peak 900 cells with above charge rates.....I felt that keeping a tighter line is more important that throwing money at a setup that can get pricey and takes up a lot of space (wires, power supply, charger, trays) vs a maha c9000 or 8 cell charger.

geeunit1014
2011.06.23, 11:17 AM
Lipo charger will definitely not work for nimh cells.. as z3zinho said the spintec ICC will work for this.. AAA's are pretty close to the same length as sub c's so it shouldnt take much to make it work. IIRC the spintec will discharge as well so its 2 birds with one stone.

z3zinho
2011.06.23, 03:02 PM
Here is the problem with a peak detection charge in a group setting (coventional charging tray) the group of 4 will only be charged to the peak capacity of the weakest individual cell....
Now if your using matched packs there is no problem until age and use creep on the cells.... .

This is in fact wrong. When you charge in series with a delta-peak charger, you are charging until the whole pack appears charged. This means that most of the times you will be overcharging the weaker cell's, making them even weaker. If you then don't equalize the cell's before charging, they will degrade rather fast. This is specially a concert if you are charging at high currents.

dr_hfuhuhurr
2011.06.23, 03:41 PM
Thanks for the info...and I'll see you tomorrow John.

Good stuff though. Thanks!

unearthed name
2011.06.23, 08:15 PM
Most locals at our track use Maha chargers (more than one!) such as the 8-cell and the c9000. Everyone I know who uses these charge and peak, I rarely see any fancy chargers. I personally don't see the need to buy an expensive charger and wire 4 individual trays to it or modify a PN/ATM tray. My maha charges my batteries just fine...

Why not just get the c9000? You can charge each battery at different settings and you get to see its current charge level and voltage. No one at our track has any issues with maha chargers and I would love to see your proof as to why "the MAHA charger doesn't really do that well for peaking packs."

BLT, what do you mean by peaking? i recently bought a maha 9000, and i'm feel that, compared to the 800 series (the one with 8 slot batteries) my car feels slower, and the batteries are warm, not hot when you're using the 800 series.

can i then using a c9000 then use another charger to peak it off? say using a lipo charger?

bermbuster
2011.06.23, 08:29 PM
This is in fact wrong. When you charge in series with a delta-peak charger, you are charging until the whole pack appears charged. This means that most of the times you will be overcharging the weaker cell's, making them even weaker. If you then don't equalize the cell's before charging, they will degrade rather fast. This is specially a concert if you are charging at high currents.

When you charge in series with a delta peak you can adjust the sensitivity of the peak....usually 0-25mv IF you set your sensitivity wrong you will over-charge. This is why you are over charging your weaker cells.....:D
Charging batteries can be an art and mastering how to do it can be challenging......:cool:

bermbuster
2011.06.23, 08:32 PM
BLT, what do you mean by peaking? i recently bought a maha 9000, and i'm feel that, compared to the 800 series (the one with 8 slot batteries) my car feels slower, and the batteries are warm, not hot when you're using the 800 series.

can i then using a c9000 then use another charger to peak it off? say using a lipo charger?

I believe he means Re-peaking....
your taking your charged pack and putting it on a few minutes before your race so it gets a re-peak so the cells will come off warm and ready to burn up some RCP......:cool:

blt456
2011.06.23, 09:03 PM
I believe he means Re-peaking....
your taking your charged pack and putting it on a few minutes before your race so it gets a re-peak so the cells will come off warm and ready to burn up some RCP......:cool:

Yes that's what I mean. I charge my batteries at my house at 1 amp and when I go to the track, all I do is just pop them in my c9000 and select a 2 amp charge rate. I do this to warm them up because I feel that it allows batteries to put out more power.

unearthed name
2011.06.23, 09:30 PM
how long is your battery life using this method?

z3zinho
2011.06.24, 07:12 AM
When you charge in series with a delta peak you can adjust the sensitivity of the peak....usually 0-25mv IF you set your sensitivity wrong you will over-charge. This is why you are over charging your weaker cells.....:D
Charging batteries can be an art and mastering how to do it can be challenging......:cool:

It doesn't change that you choose the delta-peak for the whole pack... The charger won't magically stop the charging process once the weakest cell is completely charged.

In fact, when stoping charge with delta-peak, you are supposed to overcharge, otherwise it won't work. What happens is that when a cell is completely full, it will start to dissipate the energy you are supplying to it as heat. And it's this increase in internal heat that makes the voltage drop (aka delta-peak) happen.

color01
2011.06.24, 03:21 PM
Right, and it of course follows that the lower your Delta-peak settings, the less you will overcharge your cells per cycle. Currently I charge at 1.3A with a 6mV delta peak and that's it. I still don't see the point of peaking at higher currents as the punch is lost anyways by the time I get into the right rhythm to take advantage of any extra power.

bermbuster
2011.06.24, 03:59 PM
Right, and it of course follows that the lower your Delta-peak settings, the less you will overcharge your cells per cycle. Currently I charge at 1.3A with a 6mV delta peak and that's it. I still don't see the point of peaking at higher currents as the punch is lost anyways by the time I get into the right rhythm to take advantage of any extra power.

The real trick is to learn what is the optimum peak for the type of cell your charging. If you underpeak or false peak your cells your robbing yourself of power. The best way really to charge nimh is using a temp. cut off. That is why the mahas do such a good job. I bought the multi charger so I can charge enough batteries for me and my son. I use it for all scales. Having the individual holders allows me to group new batteries into matched packs that give me consistant results. What Im finding is the quality of aaa s have really gotten much better and I dont have many "dud" cells.
My nreal problem is I dont race often and my packs get into a "flat" state from not being cycled. Most of the time I can revive them but lately I have been just replacing packs (no time to tinker).

blt456
2011.06.25, 01:22 PM
how long is your battery life using this method?

I think that runtime would depend on things such as driving style, gear ratio, motor etc...so my results compared to yours aren't probably helpful unless we have the same exact car :)